With prior art vacuum food storage containers, sometimes the only way for a user to check the presence of a vacuum was to open the container, whereupon the inward rush of air can be heard. For many users, this air noise is evocative of the presence of a vacuum and provides confidence in the storage system.
U.S. Pat. No. 7,246,555 describes cordless vacuum food storage system comprising a vacuum unit that rests on the lid of the container and uses a vacuum switch to monitor internal pressure so that a vacuum operation can take place unattended by the user to recharge vacuum lost during storage. This U.S. Pat. No. 7,246,555 patent publication also describes a more satisfactory way of providing an indication that vacuum is present in the container. Opposite sides of a diaphragm are exposed to internal and ambient pressures, and a poppet is fixed to the diaphragm so that an internal vacuum retracts the poppet, for a visual indication of the presence of a vacuum in the container, while a click spring that biases the poppet outwardly provides an audible indication of the same. Although a significant improvement compared to the old method, the visual impact of the poppet is small, due to its size and location, where it may easily be blocked from view by the vacuum unit. The audible “click” of the spring is helpful to indicate a vacuum, but it is unfamiliar and must be learned, since users do not intuitively associate such a noise with the presence of vacuum in a container.
The vacuum food storage system of U.S. Pat. No. 7,246,555 also employs a bayonet fastener, or tongue and groove fastener, for connecting the vacuum unit to the container. A drawback of this arrangement is that twisting and removing the vacuum unit is difficult and this is only partially mitigated by the cushions and ribs provided on the body to assist with gripping the unit.
It is an object of the present invention to overcome or substantially ameliorate the above disadvantages or, more generally, to provide an improved vacuum food storage system.